Oxycodone, morphine, and other opioid analgesics are successful and therapeutically useful medications, e.g., as pain killers, when administered orally. Unfortunately, they also pose a severe threat for willful abuse due to their ability to alter mood and/or cause a sense of euphoria. Traditional sustained release formulations of such drugs, which contain a relatively large amount of drug meant to be released from the formulation over an sustained time period, are particularly attractive to abusers since the sustained release action can be destroyed by crushing or grinding the formulation. The resulting material (i.e., the crushed formulation) can no longer control the release of drug. Depending on the drug, abusers can then (1) snort the material, (2) swallow the material or (3) dissolve the material in water and subsequently inject it intravenously. The dose of drug contained in the formulation is absorbed immediately through the nasal or GI mucosa (e.g., snorting or swallowing, respectively) or is administered in a bolus to the systemic circulation (e.g., IV injection), These abuse methods result in the rapid bioavailability of relatively high doses of drug, giving the abuser a “high”. Since relatively simple methods (crushing, grinding, chewing and/or dissolution in water) can be used to transform such formulations into an abusable form, they provide virtually no deterrent to a potential abuser.
For example, in recent years, there have been numerous reports of diversion and abuse of sustained release formulations of opioids such as oxycodone, oxymorphone and morphine. According to a report from the Abuse and Mental Health Services Administration, results from the 2007 National Survey on Drug Use and Health: National Findings (Rockville, Md.: US Dept. of Health and Human Services), showed that in both 2006 and 2007, an estimated 5.2 million persons aged 12 or older (2.1 percent in each year) were current nonmedical users of prescription pain relievers. Additionally, from 2002 to 2007, there was an increase among young adults aged 18 to 25 in the rate of current use of prescription pain relievers, from 4.1 to 4.6 percent. Data from this survey also supports the notion that sustained-release formulations susceptible to tampering methods such as chewing, crushing and grinding likely contributes to the increasing rates of prescription pain reliever abuse. For example, in 2007, there were an estimated 554,000 new nonmedical users of OxyContin® (a sustained release formulation of the active drug oxycodone).
Oxycodone is a controlled substance in Schedule II of the Controlled Substances Act (CSA), which is administered by the Drug Enforcement Administration (DEA). Despite the fact that Schedule II provides the maximum amount of control possible under the CSA for approved drug products, in practice it is difficult for law enforcement agencies to control the diversion or misuse of legitimate prescriptions. Although abuse, misuse, and diversion are potential problems for all opioids, including Oxycodone, opioids are a very important part of the medical armamentarium for the management of pain when used appropriately under the careful supervision of a physician.
U.S. Pat. No. 3,980,766 to Shaw et al. (“Shaw”), U.S. Pat. No. 4,070,494 to Hoffmeister et al. (“Hoffmeister”), and U.S. Pat. No. 6,309,668 to Bastin et al. (“Bastin”) describe formulations designed to prevent the injection of compositions meant for oral administration.
Shaw describes the incorporation of an ingestible solid which causes a rapid increase in viscosity upon concentration of an aqueous solution thereof.
Hoffmeister describes the incorporation of a non-toxic, water gelable material in an amount sufficient to render the drug resistant to aqueous extraction.
Bastin describes a tablet for oral administration containing two or more layers containing one or more drugs and one or more gelling agents within separate layers of the tablet. The resulting tablet forms a gel when combined with the volume of water necessary to dissolve the drug allegedly reducing the extractability of the drug from the tablet.
It should be noted that although these compositions allegedly preclude abuse by injection, this approach fails to prohibit rapid dissolution of the drug once the dosage form is crushed into smaller particles or pieces. Thus, these formulations are vulnerable to abuse by crushing and swallowing or snorting the formulation, which are commonly reported methods of abuse.
U.S. Pat. Nos. 3,773,955 and 3,966,940 to Pachter et al. describe formulations containing a combination of opioid agonists and antagonists, in which the antagonist does not block the therapeutic effect when the admixture is administered orally, but which does not produce analgesia, euphoria or physical dependence when administered parenterally by an abuser.
U.S. Pat. No. 4,457,933 to Gordon et al, describes a method for decreasing both the oral and parenteral abuse potential of strong analgetic agents by combining an analgesic dose of the analgetic agent with an antagonist in specific, relatively narrow ratios.
U.S. Pat. Nos. 6,277,384, 6,375,957 and 6,475,494 to Kaiko et al. describe oral dosage forms including a combination of an orally active opioid agonist and an orally active opioid antagonist in a ratio that, when delivered orally, is analgesically effective but that is aversive in a physically dependent subject. While such a formulation may be successful in deterring abuse, it also has the potential to produce adverse effects in legitimate patients.
The FDA recently approved two sustained release formulations of opioid active ingredients with tamper resistant features. A sustained release oxycodone tablet, designed to resist crushing and to gel in the presence of water, is currently available. Also, a multiparticulate-in-capsule product containing morphine and a sequestered naltrexone is also commercially available; this product is designed to release naltrexone (an opioid antagonist) to counteract the euphoric effects of the opioid active ingredient when the formulation is crushed, chewed or dissolved. While such formulations offer an improvement over previously available formulations with respect to susceptibility to tampering, there are disadvantages associated with the available products. For example, tablet formulations that are difficult to crush, but not crush-proof, can still be chopped or shredded into small particles and do not address the needs of patients with difficulty swallowing, and formulations containing antagonists have the potential to cause harm to legitimate patients.
It is therefore an object of the present invention to provide a pharmaceutical composition (e.g., a multiparticulate composition) that reduces the potential for improper administration of drugs without the addition of aversive agents or antagonists, which have the potential to cause harm to legitimate patients. Such a formulation significantly reduces the potential for improper administration or use of drugs but, when administered as directed, is capable of delivering a therapeutically effective dose. Methods of making and using such a formulation are also provided.